The relationship of Radha and Krishna is the embodiment of love, passion and devotion. Radha's passion for Krishna symbolizes the soul's intense longing and willingness for the ultimate unification with God. Shri Krishna is the soul of Radha and Radha is definitely the soul of Shri Krishna. She is the undivided form of Shri Krishna. She will remain a mystery unless one can know her inexpressible divine elements.
Shri Krishna is not only the ultimate object of all love, but also is the topmost enjoyer of all loving relationships. Therefore, in the dynamic and expanding form of Krishna, He has unlimited desires to enjoy spiritual loving relationships known as leela. To do this, He expands Himself into the dual form of Krishna and Radha, His eternal consort and topmost devotee. In other words, Radha is the feminine aspect of Lord Krishna and is non-different from Krishna, but together (both the masculine and feminine aspects). They fulfill the purpose of engaging in sublime loving leela to exhibit supremely transcendental loving exchanges.
Radha Krishna is the original principle of loving relationships (conjugal Love). The sex principle exists in the Absolute in its pure form without any inebriety or impurity, because Krishna is in fact Radha. In other words, the Lord is one, but for His pleasure and enjoyment, He expands himself to enjoy loving relationships. The original expansion is Radha. Together, Radha and Krishna enjoy eternal pastimes of transcendental love.